Noves troballes en el llevat Saccharomyces cerevisiae

Investigadors de la UAB, en col·laboració amb la Universitat de Stellenbosch (Sudàfrica), acaben de descriure l'estructura de l'enzim PPC descarboxilasa (PPCDC) en el llevat Saccharomyces cerevisiae, organisme d'enorme interès biotecnològic i excel·lent model per a la investigació biològica. Els científics han comprovat que aquesta estructura difereix substancialment de la que hi ha en els humans, el que, juntament amb el seu caràcter d'enzim essencial, el converteix en una potencial diana terapèutica.Investigadores de la UAB, en colaboración con la Universidad de Stellenbosch (Sudáfrica), acaban de describir la estructura del enzima PPC descarboxilasa, (PPCDC), en la levadura Saccharomyces cerevisiae, organismo de enorme interés biotecnológico y excelente modelo para la investigación biológica. Los científicos han comprobado que ésta difiere sustancialmente de la que tiene en los humanos, lo que, junto a su carácter de enzima esencial, la convierte en una potencial diana terapéutica.Researchers at UAB in collaboration with the University of Stellenbosch, South Africa, have discovered the structure of the PPC descarboxilase (PPCDC) enzyme present in the yeast Saccharomyces cerevisiae, a very important organism in biotechnology and an excellent model for biological research. Scientists have verified that its structure differs substantially from that found in humans, which, in addition to its characteristic as an essential enzyme, makes it a potential therapeutic target

Una proteïna, tres funcions

Ja fa gairebé tres dècades el descobriment de proteïnes que podien realitzar dues funcions diferents va suposar un punt de ruptura en la percepció clàssica de la biologia molecular, desafiant el concepte "una proteïna, una funció". Recentment, un equip internacional liderat per investigadors de la UAB ha trobat en un llevat un gen que codifica una proteïna que realitza tres funcions, diferents però importants per mantenir l'estabilitat genòmica i evitar la ruptura del DNA.Hace ya casi tres décadas el descubrimiento de proteínas que podían realizar dos funciones diferentes supuso un punto de ruptura en la percepción clásica de la biología molecular, desafiando el concepto "una proteína, una función". Recientemente, un equipo internacional liderado por investigadores de la UAB ha encontrado en una levadura un gen que codifica una proteína que realiza tres funciones distintas, pero todas ellas importantes para mantener la estabilidad genómica y evitar la ruptura del DNA.Almost three decades ago,the discovery of proteins that could perform two different functions was a breaking point in the perception of classical molecular biology, changelling the concept of "one protein, one function". Recently, an international team lead by researchers from the UAB found a yeast gene encoding a protein that performs three different functions, important for maintaining genomic stability and prevent DNA breakdown

Els efectes de la manca de potassi a la cèl·lula

Els efectes de la manca de potassi, un catió primordial en la majoria dels éssers vius, en les cèl·lules del llevat Saccharomyces cerevisiae ha estat estudiada per un grup d'investigadors de la UAB. L'escassetat d'aquest element pot afectar diversos aspectes de la fisiologia de la cèl·lula, alguns dels quals encara desconeguts. Aquesta investigació en revela noves funcions que poden ser extrapolades també a plantes i animals.Los efectos de la falta de potasio, un catión primordial en la mayoría de los seres vivos, en las células de la levadura Saccharomyces cerevisiae han sido estudiados por un grupo de investigadores de la UAB. La escasez de este elemento puede afectar varios aspectos de la fisiología de la célula, algunos de los cuales todavía desconocidos. Esta investigación revela nuevas funciones que pueden ser extrapoladas también a plantas y animales

Els llevats com a organisme model de recerca en biologia

Els llevats, i en particular el llevat Saccharomyces cerevisiae, han estat durant molts anys un excel·lent organisme model per a estudis fonamentals en bioquímica, biologia cel·lular i genètica eucariòtica, i també per a la recerca aplicada. S. cerevisiae acumula una sèrie d'avantatges que no es troben en altres models, com un genoma compacte, una genètica senzilla i una manipulació molt fàcil, i és especialment adequat per a les aproximacions d'alt rendiment en genòmica, proteòmica i interactòmica. Per aquesta raó, és l'organisme d'elecció per desenvolupar i verificar noves tecnologies i per investigar processos biològics fonamentals i conservats evolutivament.Yeasts, and particularly the budding yeast Saccharomyces cerevisiae, have been for many years an outstanding model organism for fundamental studies in eukaryotic biochemistry, cell biology and genetics, as well as for applied research. S. cerevisiae accumulates a number of advantages that are not found in other models, such as a compact genome, straightforward genetics and easy manipulation, and it is particularly suitable for highthroughput genomic, proteomic and interactomic approaches. For that reason it is the organism of choice to develop and test new technologies and to investigate fundamental and evolutionarily conserved biological processes

Deportividad y violencia en el fútbol base : un programa de evaluación y de prevención de partidos de riesgo

This studys primary objective was to evaluate sportsmanship and violence in soccer matches. In order to do so, all the trainers and referees in one of the feeder teams categories of the Zaragoza and Vitoria Football Clubs took part as experts and judges in drafting a football match evaluation checklist. Two trainers and a referee used this checklist after each match to evaluate the degree of sportsmanlike/unsportsmanlike behaviours that had taken place. The results of the evaluations of all the matches in the 2005-2006 season show that parents and spectators displayed the most unsportsmanlike behaviours, followed by the same types of behaviour in players and trainers. There was a lower incidence of violent, unsportsmanlike behaviours. This studys second objective was to evaluate a protocol to prevent violent incidents during high-risk matches in the leagues second round. This process consisted in signing a collaboration agreement with the training staff of teams that had displayed violent behaviour in the leagues first round. The trainers of these teams were trained to hold meetings and conduct specific exercises during team training sessions to encourage parents and players to behave in a sportsmanlike manner. The results show the positive contribution of these protocols, not only in the absence of violent incidents during high-risk matches, but also in the higher scores on the football match evaluation checklist achieved by participant trainers during the leagues second round, compared with non-participant trainers in the same category

Genome-wide recruitment profiling of transcription factor Crz1 in response to high pH stress

Background: Exposure of the budding Saccharomyces cerevisiae to an alkaline environment produces a robust transcriptional response involving hundreds of genes. Part of this response is triggered by an almost immediate burst of calcium that activates the Ser/Thr protein phosphatase calcineurin. Activated calcineurin dephosphorylates the transcription factor (TF) Crz1, which moves to the nucleus and binds to calcineurin/Crz1 responsive gene promoters. In this work we present a genome-wide study of the binding of Crz1 to gene promoters in response to high pH stress. Results: Environmental alkalinization promoted a time-dependent recruitment of Crz1 to 152 intergenic regions, the vast majority between 1 and 5 min upon stress onset. Positional evaluation of the genomic coordinates combined with existing transcriptional studies allowed identifying 140 genes likely responsive to Crz1 regulation. Gene Ontology analysis confirmed the relevant impact of calcineurin/Crz1 on a set of genes involved in glucose utilization, and uncovered novel targets, such as genes responsible for trehalose metabolism. We also identified over a dozen of genes encoding TFs that are likely under the control of Crz1, suggesting a possible mechanism for amplification of the signal at the transcription level. Further analysis of the binding sites allowed refining the consensus sequence for Crz1 binding to gene promoters and the effect of chromatin accessibility in the timing of Crz1 recruitment to promoters. Conclusions: The present work defines at the genomic-wide level the kinetics of binding of Crz1 to gene promoters in response to alkaline stress, confirms diverse previously known Crz1 targets and identifies many putative novel ones. Because of the relevance of calcineurin/Crz1 in signaling diverse stress conditions, our data will contribute to understand the transcriptional response in other circumstances that also involve calcium signaling, such as exposition to sexual pheromones or saline stress

The inhibitory mechanism of Hal3 on the yeast Ppz1 phosphatase : A mutagenesis analysis

The Ser/Thr protein phosphatase (PPase) Ppz1 is an enzyme related to the ubiquitous type-1 PPases (PP1c) but found only in fungi. It is regulated by an inhibitory subunit, Hal3, which binds to its catalytic domain. Overexpression of Ppz1 is highly toxic for yeast cells, so its de-regulation has been proposed as a target for novel antifungal therapies. While modulation of PP1c by its many regulatory subunits has been extensively characterized, the manner by which Hal3 controls Ppz1 remains unknown. We have used error-prone PCR mutagenesis to construct a library of Ppz1 variants and developed a functional assay to identify mutations afecting the binding or/and the inhibitory capacity of Hal3. We have characterized diverse Ppz1 mutated versions in vivo and in vitro and found that, although they were clearly refractory to Hal3 inhibition, none of them exhibited signifcant reduction in Hal3 binding. Mapping the mutations strengthened the notion that Hal3 does not interact with Ppz1 through its RVxF-like motif (found in most PP1c regulators). In contrast, the most relevant mutations mapped to a conserved α-helix region used by mammalian Inhibitor-2 to regulate PP1c. Therefore, modulation of PP1c and Ppz1 by their subunits likely difers, but could share some structural features

Analysis of Two Putative Candida albicans Phosphopantothenoylcysteine Decarboxylase / Protein Phosphatase Z Regulatory Subunits Reveals an Unexpected Distribution of Functional Roles

Protein phosphatase Z (Ppz) is a fungus specific enzyme that regulates cell wall integrity, cation homeostasis and oxidative stress response. Work on Saccharomyces cerevisiae has shown that the enzyme is inhibited by Hal3/Vhs3 moonlighting proteins that together with Cab3 constitute the essential phosphopantothenoylcysteine decarboxylase (PPCDC) enzyme. In Candida albicans CaPpz1 is also involved in the morphological changes and infectiveness of this opportunistic human pathogen. To reveal the CaPpz1 regulatory context we searched the C. albicans database and identified two genes that, based on the structure of their S. cerevisiae counterparts, were termed CaHal3 and CaCab3. By pull down analysis and phosphatase assays we demonstrated that both of the bacterially expressed recombinant proteins were able to bind and inhibit CaPpz1 as well as its C-terminal catalytic domain (CaPpz1-Cter) with comparable efficiency. The binding and inhibition were always more pronounced with CaPpz1-Cter, indicating a protective effect against inhibition by the N-terminal domain in the full length protein. The functions of the C. albicans proteins were tested by their overexpression in S. cerevisiae. Contrary to expectations we found that only CaCab3 and not CaHal3 rescued the phenotypic traits that are related to phosphatase inhibition by ScHal3, such as tolerance to LiCl or hygromycin B, requirement for external K+ concentrations, or growth in a MAP kinase deficient slt2 background. On the other hand, both of the Candida proteins turned out to be essential PPCDC components and behaved as their S. cerevisiae counterparts: expression of CaCab3 and CaHal3 rescued the cab3 and hal3 vhs3 S. cerevisiae mutations, respectively. Thus, both CaHal3 and CaCab3 retained the PPCDC related functions and have the potential for CaPpz1 inhibition in vitro. The fact that only CaCab3 exhibits its phosphatase regulatory potential in vivo suggests that in C. albicans CaCab3, but not CaHal3, acts as a moonlighting protein

Coordinate responses to alkaline pH stress in budding yeast

Alkalinization of the medium represents a stress condition for the budding yeast Saccharomyces cerevisiae to which this organism responds with profound remodeling of gene expression. This is the result of the modulation of a substantial number of signaling pathways whose participation in the alkaline response has been elucidated within the last ten years. These regulatory inputs involve not only the conserved Rim101/PacC pathway, but also the calcium-activated phosphatase calcineurin, the Wsc1-Pkc1-Slt2 MAP kinase, the Snf1 and PKA kinases and oxidative stress-response pathways. The uptake of many nutrients is perturbed by alkalinization of the environment and, consequently, an impact on phosphate, iron/copper and glucose homeostatic mechanisms can also be observed. The analysis of available data highlights cases in which diverse signaling pathways are integrated in the gene promoter to shape the appropriate response pattern. Thus, the expression of different genes sharing the same signaling network can be coordinated, allowing functional coupling of their gene products